Relativity
by KifKathleen
Summary: A chance meeting between the Doctor and Rose's great-grandmother leaves Rose wondering just what her great-granny knows and how she knows it.


**Author's Note:** This is just a bit of fluff that popped into my head while watching my favorite episode. The first part is set during "Aliens of London"; the second, just after "Boom Town". (Although it's just coincidence that both episodes feature Slitheen; they won't be making any appearances in the story.)

**Chapter Disclaimer:** Sadly, I don't own Doctor Who and make no profit from it.

* * *

Rose weighed the TARDIS key in her hand, leaned against the railing of the walkway outside her flat, smiled shyly at the Doctor, tried to strike a balance between showing appropriate gratitude and playing it cool, as if receiving her own personal key to a spaceship weren't one of the most exciting things ever to happen to her.

The moment was broken when an old woman appeared at the top of the stairs. "My little Rose!"

"Great-granny Nelson! What are you doing here?"

"I may be arthritic, but I think I can still manage to phone for a cab when my great-granddaughter shows up out of the blue after a year." She kissed Rose's cheek.

"Yeah, right, sorry about that," said Rose, an apology that had become second nature over the last few hours. "Oh, Doctor, this is –"

"Great-granny Nelson, yes, I gathered. Nice to meet you. Well, I'll just leave you to your reunion, shall I? See you later, Rose." He tried to slide past them, but was stopped by a wrinkled hand on his arm.

"Oh no, you don't. You're not swanning off without a proper goodbye, not this time." She took his head in her hands, pulled it down towards her, planted a kiss on his forehead. The Doctor was too surprised to protest. "Now, I certainly hope that you are taking good care of my Rose, young man."

"He's not my… We aren't a couple, Granny," said Rose – yet another refrain she was weary of repeating today.

"Well, whether you are or you aren't, I'm still going to want to know that someone's looking out for you, aren't I? Because this one, he has a nose for trouble, I can tell. Lord knows he's gotten you in enough trouble with your mother. I tried to tell her that you were fine, that you were just larking about seeing the world, but she wouldn't listen. And why should she have done? What did I know?"

At some point during this speech, the Doctor had stopped looking as if he were trying to escape. Now he was leaning back against the railing, arms crossed, expression somewhere between amused and fascinated.

"And then, you were gone so long," the old woman went on. "Just how long were you gone, anyway?"

"It's been a year, Granny."

"No, that's how it seemed to us. But you are a considerate child; you wouldn't just disappear on purpose for a whole year without letting us know you were all right. So how long were you really gone?"

"Granny, remember how I used to work at Henrik's? But then the shop blew up; do you remember that?" Rose was using the slow, loud, bright voice that people reserve for the doddering elderly. But before she could continue, the Doctor cut in.

"It's just been a couple of days."

"Doctor!" Rose whispered, aghast, but he ignored her.

"One trip to the future, one trip to the past. I meant to have her back before anyone missed her. But the landing went a bit pear-shaped."

"I'll say," both women said in unison.

"How did you know?" he asked.

Granny opened her mouth, then caught herself. "Wait, one trip to the past, you said? What past?"

His lips twitched, eyes crinkled. "Slightly before your time, I should think. We met Charles Dickens."

"Well, then, I think I'd better not say."

"Fair enough."

"But I will say that I never got the chance to thank you properly, both of you. You saved so many people that day, Doctor. And you, Rose, you gave me hope, when hope was in short supply."

Rose could only stare, gobsmacked, but the Doctor took it in stride. "I'm sure you were-slash-will be welcome. I really do need to be off now, but I look forward to meeting you, Great-granny Nelson." And then he was gone, leaving Rose alone with the family matriarch, who was now tight-lipped in response to all of Rose's attempts to learn what she knew and how she knew it.

* * *

_Some months later_

Jack looked up and down the TARDIS corridor; the coast was clear. He stepped across the threshold of Rose's bedroom, a thrill running down his spine at the bold and dangerous move.

Rose looked up from where she sat cross-legged on the bed, a photo album spread across her lap, and gave him a smile that didn't quite reach her eyes.

"Glad to be clear of Raxicoricofallapatorius?" Jack kicked himself for not preparing a better opening line; his flirting skills were unexpectedly deserting him. Keeping one eye and one ear out for the Doctor was taxing his concentration.

"Yeah, I'll say. I mean, I know they're not all Slitheen, but they still gave me the creeps."

With one last glance over his shoulder, Jack came to sit next to her on the bed. "So what are you looking at?"

"Oh, just..." She laughed, a hollow sound. "Just feeling nostalgic after the whole Mickey thing, you know? Thought I'd pull out some family photos."

Jack stifled a sigh. Right now, Rose needed a friend, not a lothario. He could do that. "So who've we got here?"

She ran her fingers over a picture of a group of children ranging from toddlers to teens. "That's me with my cousins – I think I was about ten. And then this one here is my dad with his brother and sister."

"And that one?" Jack pointed out a picture of Rose with three other women of various generations and a middle-aged man.

"Oh, the Nelson gang, that's what Mum calls this one." She ran her fingers over each face as she identified it. "That's my mum. And her mum, my Granny Prentiss – Granny Rose. I was named after her. And that's Granny's brother, Great-uncle Jamie, and her mum, Great-granny Nelson. She was…" Her fingers stilled, her lips pursed, her brow creased in puzzlement.

"She was what?"

"Doctor!" Rose called.

In a heartbeat, Jack was on his feet, leaning casually against the bedpost, gazing around the room as if he hadn't even noticed that it had another occupant. And none too soon – the Doctor appeared in the doorway with a speed that made Jack suspect the Time Lord had been lurking just outside. His glare in Jack's direction said that he wasn't at all fooled by the innocent air.

"Doctor, come look at this." The Doctor settled himself into the recently vacated spot next to Rose and leaned over her shoulder. "You remember Great-granny Nelson?"

"The one who kissed me, rather than slapping me like another member of your family who shall remain nameless? Yes, I'd say she stuck in my memory."

"This is her, right here. Nancy Nelson. And her son Jamie."

"Yes."

"Nancy, Jamie. Don't you see? That's how she knew you! The Blitz, the gas masks, the empty boy – it was my great-grandmother and my great-uncle!"

"Yes."

"Wait, you knew? How did you know?"

He tapped his nose. "Like I told her, my nose has special powers. Her face had changed, but her scent hadn't."

"Why in the world didn't you say anything?"

"What was I supposed to say? 'Hey, Rose, this girl is going to become your great-grandmother in a few decades, but don't let on or else you'll change the course of history'?"

"Yes, exactly!"

"Really?" He looked surprised. "Oh. Well, then, I'll remember that the next time we run into one of your ancestors."

Rose snorted at that, then frowned in thought. "But wait, Granny Rose wasn't born yet. So that means…that means…"

"…That you were named after someone who was named after you, yeah." He smiled at her, the proud smile of a teacher with a particularly apt student.

"How is that even possible?"

"Well, you have to understand, time is not strictly linear. It's more sort of a jumbly…jumble." He waved his hands in an attempt to illustrate the concept of jumbliness, and shook his head. "Someday I'll come up with a catchier way of explaining that."

Rose sat quiet for a moment, pondering the tangled weave of time. Then without warning she reached up and kissed the Doctor's cheek. His eyebrows leapt, his hand flew up of its own accord to touch the spot. "What was that for?"

"For saving my family. For saving the world. For just being generally…" She searched for a word, then grinned. "Fantastic."

His face lit up and he jumped to his feet, tugging at her hand. "Well, come on then, time and space are waiting. And thanks to Mickey, you've got your passport. So where to next?"

But Rose didn't budge. The grin faded at the mention of Mickey; the melancholy look that Jack had seen when he first entered settled back down. "You and Jack go on. I feel like just hanging out here for a while."

The Doctor stared down at her, his brow furrowed, his brain churning to sort out the mystery of Rose's mercurial mood, what he was supposed to do, how he should respond. Jack stifled a sigh. Right now, the Doctor needed a nudge in the right direction. Jack could do that. "Why don't you go set a course for us, Doctor? I'll stay here and keep Rose company."

As expected, the Doctor responded to this suggestion by planting himself back down by Rose's side. "Know what? Time and space can wait. Got any more of Granny Nelson in that album?" He threw Jack a look that made the younger man resolve to stay well away from the exterior door while the TARDIS was in motion from now on – why tempt fate or a Time Lord to dump him out into the Time Vortex? But, Jack decided, Rose's smile as the Doctor leaned over her shoulder made it all worth while.


End file.
